Ion exchange process with magnetic ion exchange resins



Patented June 16, 1953 ION. EXCHANGEP-ROCESS 'WI THMA GNETI C .IONEXCHANGE RESINS 7.-Ea"rl*C.E'Herkenhofl'y Stamford, 001111., assignor1:0e-American:.Cyanamid Company, New York, 1N. Y., a;corporation ofMaine No Drawing. "ApplicatiomAugust 1 6, 19 46, r -SerialNo. 689,811

This invention relatesto ion exchange resins and more. particularly,tomagnetic or magnetized ion-exchange resins which are amenableto;separatio'rr'fromnonemagnetic ion exchange resins in admixture.therewithnby magnetic .means.

Manyadvantages. are. attainedupon use .of .in: tirnately; .mixedLion.exchange resins. in .placeof the..more -conventional .eset-up ofseparate beds in ..liquid .demineralization processes. Forexample,-.'mixed.resins oftengivemoreeflicient and. more.completedemineralization. Moreover, they permit the useofconventionaltypesof equipment for liquid demineralization and do notrequire special equipment. Whenmixedresins are used in disposablecartridges; many advantages are apparent. These include reduction in.pack ing labor, increase in packing machine capacity, eliminatiomoftha'neces'sity. for separatorscreens between nmultiple zbeds, increasediquant'ity of waterperhhitvolume of exchange materiahlack of"highzacidity-in the liquid to befdemineralimd due :to immediateneutralization, etc. "Mixed resins are :ajlso liseful in commercialinstallations either-in the for-mrof beds or: as 'filter coatings,

either in batch processes or =in continuous processes.

-' One outstanding "disadvantage in the E use of mixed resins lies inthe excessive: waste of material heretofore-necessarily inherent in-the-process. "The ion exchange resins are too-expensive for practicablediscarding afteronly one -=cycle of demineralizationpan'd' usu'a'llymust be regenerated and then reused. *The separation of -a specifictype-of ion exchange resin from-mixtures with 1 other I types of resins""forregeneration*or' other purposes has in the past presented a difiicult-problem. I

1 Separation of mixtures of ion exchange resins andsubsequent' reuse ofthe resinsafter suitable regeneration is jproposedby 'Alexander V. -Aimin his copending application," Serial No."689.,80'7 filed August 10,'1946, "now i'abandoned. .The Alm application "describes in detail"methods of separation including particularly *fro'th flotationprocesses, V I f "Separation of one ion exchange. resin from another inadmixture therewith by sink, and float methods using a heavy gravitymedium. anflparticularly, .using muds or ,suspensoi'dsgof ifinely ground1 solidmaterials. as the. heavy gravity. vme-.dium',1hasalsdbeenproposed. T I

Itvis an, object of 'thepresent inventionto efiect separation of .mixedion nexchange -.resins ,l, one from .the other, by ,means, of magnetic:separa- .tion. I

{A ,furtherz:objectnofithemresent: inventioni'is,

. therefore, s'bhe :;-preparation. :of magnetic 1 ion exchangemesinswhich vareaamenable toitmagnetic separation -.from'-rnon1-' -magne.tic"ion exchange resins.

r- Another Eobje'ctzfofrfthe zpresent :invention: isfzto provideia:processx for;preparingimagnetic ion: exchange resins. :Still-anotherobject: of the'ipresentinvention" is to 1 provide a process foridemi'neralization o'fia liquid which: includes'-::bringingrthe :liquid'into contact? with=;a-:mixture vjofrcation and anion -exchangeresins,*atileastzzone, of. which. ismagneticallyrecoverable; frombtheothers, separatingi the mixturewrof resinsr fromithe demineralizediliquid byirfiltration,rdecantation,rfrothofiotation .or anyother-suitable means'pand 'iurtheri separating 1 the magnetic ionexchange resin from the other-resin orrres'ins: by? meanscofsniagneticrseparation.

Thesexsand'zother objectsraareizattained ibyi-i'incorporating.aparticles cof' a :Lmagn'etic' nsub'stance with an ion exchange resineither during or after its preparation, using the resulting magnetic ionexchange-resin as -a; component of -a *mixture of ion exchange resins,bringinga liquid containing ionizable solids into contact'with themixture of ion exchange resins which includes the magnetic resin,separating the,;demineralized liquid from the mixture of resins, andremoving the magnetic resin-from?theotheriresintor resins 'of 1 the"mixtureby: meansofrmagnetic separation. The difierent type ;-resins "are1 regenerated V separately, then premixed and treused to remove.ionizable solids from liquids containing; same.

The invention will be described in greater detail in conjunction 'withthe following specific examples. in which the, proportions are given inparts" by. weight. 'lTheexamples; arev merelyillustrative. and, it .is-.not, intended that the scope. .of "the invention. should .be limitedto ;the details thereof.

material, and activated, granular, anion active material, one of whichion active materials hasbeen.mademagneticinaccordance.withthe.presentlinvention. V

- fA-flliqu id containing ,i'onizable. ands is 1 passed through thelbemof mixed, resin.in..the cylinder from ,thel liquid. isexhausted, .thelliquidsupplyto resin.

the bed of mixed resin is shut off and the mixture of resins is removedfrom the vessel.

The magnetic ion active material is then separated from the non-magneticion'active material by means of a magnet or other magnetic separator;The anio'n active resin so separated from the resin mixture isregenerated by treatment with an alkali and the cation active resin, bytreatment with acid. The regenerated resins are then remixed and themixture is reused ior further liquid demineralization.

Example 2 A Parts f Phenol (1 mol); a 94 Anhydrous sodium 'bisulfite(0.25 mol) 26 Anhydrous sodium sulfite (0.25'mol) 31.5

37% formalin (2.5 mols) 202.5 325 mesh magnetite (15% by weight of thefinal cured resin) 34 All of the above ingredients except the magnetiteare charged into a suitable .vesselequipped with means for agitation, areflux condenser and a' thermometer. An exothermic reaction takes placeand the temperature of the batch rises to refluxing which occurs atabout 100 C. Refluxing is continued until a viscous syrup isobtained, 1. .e., about 2 hours. I

The magnetite is then added to the resinsyrup and the mixture agitatedfor about 5 minutes.

The viscous syrup containing the finelydivided Example '3 Example 2 isrepeated with about 23 parts of magnetite, 10% by weight of the finalcured resin,

instead of 34 parts. The resin obtained is attracted to a magnet.

, Ea:ample 4 V 0 Example 2 isrepeated using a 325 mesh ferrosiliconwhich contains 15% silicon in place of the magnetite. A resin having acapacity for the removal of cations from solution and the property ofbeing attracted by a magnet is obtained, 1

Example 5 Example2 is repeated using an extremely finelydivided magneticiron oxide obtained as a by product in the production of aniline byreduction of nitrobenzene in thepresence of iron instead of themagnetite. The product obtained has satisfactory magnetic propertieswhich make it susceptible' to separation from non-magnetic material bymeans of a magnet, and it has a capacity for the removal of cations fromsolution.

Example 6 10 parts of anion active resin A, prepared as described indetail below, are placed in a suitable container and activated bytreatment with 'a dilute solution of sodium carbonate. An equal quantityof the magnetic product of Example 2 is activated by passing a dilutehydrochloric acid solution through a bed of the resin. The activatedcation and anion exchange resins are then mixe together, and the mixtureis used for the demineralization of liquids as described in Example 1.

Example 7 Parts Anion activeresin prepared according to the processdescribed in U. S. Patent No. 1

2,285,750 1 210 ,325 mesh magnetite 40 40 B. sodium silicate Water V 30The magnetite, sodium silicate, and water are I mixed together to form aslurry and the granulated resin is'then addedto the mixture; Afterthorough mixing in order to distribute the ma netite and the sodiumsilicate evenlycover the ,resin particles, the product is dried at 110C.

The dried product has a capacity for the removal of anions from solutionand is attracted by a magnet.

' Example 8 10 parts of a cation active resin prepared according to theprocess of Example 5 of U. S. Patent No. 2,372,233, are activated bytreatment with 'a dilute hydrochloric acid solution. An equal quantityof the magnetic product of Example 7 is activated by passing a dilutesolutionof sodium carbonate through a bed of the resin. The activatedcation and anion exchange. resins are thenmixed together, and themixture is used for the dmineralization of liquidsaccording to Example1.

Preparation of anion active resin A: 1

,w V Parts Tetraethylene pentamine (1.1-mols) 203 Epichlorohydrin (3.2mols) -1 .2 97 Water V 7 I 500 The tetraethylene pentamine ischarged-into a suitable reaction vessel provided with an agitator and ameans for cooling the vessel. The water is added to the .tetraethylenepentamine, the resulting solution is cooled to about-.44-47 0., and theepichlorohydrin is addedslowlywhile the reacting mixture .is beingcontinuously agitated and kept at a temperature between 44-47' C; Afterall the epichlorohydrin has been added the resulting syrup ismaintainedat a temperatureof about 50 C. for about-8' hours.

The gelled syrup is then heated or cured at a temperature of about-105IC. for 17-18 hours. The cured resin-is ground and screened and the20-40 mesh material set aside for use in the resinous mixtures of thepresent invention.

, The present invention is not limited to the addition of' anyparticular quantity of magnetic substance to the resin. While I preferto use about 15% by weight based on the final cured'resin of.

the magnetic substance, equally satisfactory results may be obtainedwithin a range of about-2% to about 40% magnetic material, dependingupon the strength of the magnetic field that is to be employedfor-separation, the fineness of the magnetic-medium, the density ofresin that isdesired, etc. -In general, the amount of. magnetic materialincorporated with the resin must be sufficient to render substantiallyevery particleiof resin susceptible to recoveryby magnetic means.

Other finely ground magnetic substances than magnetite maybe used in thepresent invention.

The'magnetic substances so used should be, relatively insoluble in theresin syrup into'which, they are incorporated and generally, theirsolubility in the syrup should not exceed about 10%. Some examples ofsuitable substances are vferrosilicon, magnetic iron oxide obtained fromthe production of aniline by reduction of nitrobenzene'in the presenceof iron, tieel grit; roll" scale; cobalt.

nickel, alloys. of cobalt and: nickel andypartieu ticles; by: means ofabinding agent as described.

inExample '7'; Binding a ents other thansodium silicate. including thealkali metal silicates. in general and, certain. carbonaceous binders:are also suitable for. use in accordancewith the process of the presentinvention.

In general, I, prefer, incorporating the finely ground magneticsubstance with the resin syrup during preparation of: the resin. if thereaction mixture is-ialkalineg or. weakly acid; :If the reaction,mixture is strongly acid, however, bet,- ter results are usuallyobtained if the magnetic substanceis 'bound'to the ,cured or uncull diresin particles by'means of a suitable binder. ltshould be understood;however, that the present invention is not limited to either method ofpreparation of the magnetic ion active resin.

The-present invention is not limited in any sense to a particular methodof separation-of the magnetic, resin particles fromv the non-maeneticresin particles. On a smallscale this may even be done with a hand'magnet. Ingeneral commercial applications, however, it will beadvantageous to utilize continuous magnetic separators such as, forexample; the Crockett and Stefi'ensen types. I

The present, invention is applicable to any ion exchange resin, cationor anion active. For exampl t e. c t o -activeresin may b a u u amineral acid halide condensation product as described in the copendingapplication of James ;R. Dudley, Serial No. 528,768 filed March 30,1944, now Patent No. 2,408,615, a sulfonated or phosphonated resinifiedfurfural as described in the copending application of Jack T. Thurston,Serial No. 652,235 filed March 5, 1946 now Patent No. 2,525,247, analdehyde condensation product of a sulfonated hydroxy aromatic compoundcontaining an activating group such as a ke'tone group as described inthe copending application of Jack T. Thurston, Serial No. 541,480 filedJune 21, 1944 now Patent No. 2,440,669, and the like. In addition,furfural or formaldehyde condensation products of the reaction productof acetone, furfural and sodium bisulfite as described in Patent No.2,372,233, polyhydric phenol-aldehyde condensation products such as thecatechol tannin-formaldehyde condensation products, aromatic sulfonicacid condensation products as described in Patent No. 2,204,539,carbonaceous substances, 1. e., sulfated or sulfonated carbonaceousmaterials such as coal, peat, lignite, etc., may also be used.

The cation active resins may be hydrogen activated or, if softening isdesired rather than complete demineralization, they may be used on asodium cycle. If the cation active materials are to operate on thehydrogen cycle, the resin may be activated by treating the resins withacid solutions, e. g., 0.1%-% of hydrochloric acid, sulfuric acid, etc.If the cation active materials are to be operated on the sodium cycle,they should be activated by treating with a salt solution such as anaqueous solution of sodium chloride.

Anion active resins which may be rendered magnetic and then separatedfrom mixtures with nonsmagnetic resins include condensation products ofacetaldehyde, formaldehyde, and

polyalkylene polyamines. (copending application of Jack T. Thurston,Serial'No. 643,836fi'led January 26, 1946 now abandoned), condensation.

products of 'polyalkylene polyamines with acrylonitrileammonocarbonicacid adducts .(copend i'ngapplication of James R. Dudley, Serial No.651,375, filed March 1, 1946 now U. S. Patent 2,473,498), condensationproductsof aminotriazines, guanido compounds and aldehyde's (copendingapplicationof James R. Dudley, Serial No. 607,277 filed July 26; 1945now abandoned), condensation products of aminotriazines, aldehydes andstrongly basic non-aromatic amines (copending application of James R.Dudley, Serial No. 649,127 filed February 20, 1946 now Patent No.2,529,142), biguanide-aldehyde condensation products insolubilized byureaor aminotriazine-formaldehyde condensation productsasdescribed-inlthe Swain Patent No. 2,251,-

234, crotonaldehyde, formaldehyde and poly-I alkylenepolyaminecondensation products (copending application of James R. Dudley, SerialNo. 648,838 filed January 26, 1946 now aban doned), condensationproducts of polyepoxy compounds and polyamines (copending applicationofJJames R. Dudley, SerialNo. 655,005 filed MarchlG, .11946 now. PatentNo. 2,469,684), aldehydecondensation products of furyl' aliphatic aminescopending application of James R. Dudley,:Seria11No. 642,416fi'led'January. 19, 1946 now U; 'S. Patent.:2,5:25,480'), condensationproducts of glycerol dichlorhydrin and alkylene polyamines (copendingapplication ofLenna-rt A-. Lundberg,

Serial'No. 624606 filed October 25, '1'9451now- Pat-- ent- No.2,469,693), insolubilized': guanyl ureaaldehyde and phenylbiguanide-aldehyde condensation products (copending. applications of-RobertC. Swain, Serial Nos. 368,105 filed. November 30, 1940nowlabandonedand 443,939 filed May 21, 1942, now abandoned,respectively), condensation products of polyacrylic acid with polyamines(copending application of James R. Dudley, Serial No. 648,818 filedFebruary 19, 1946 now Patent No. 2,582,194), insolubilizedpolyaminealdehyde condensation products copending applications of JamesR. Dudley, Serial Nos. 442,- 281 and 442,282 filed May 8, 1942 both nowabandoned, and Serial No. 633,859 filed December 8, 1945 now Patent No.2,521,664), etc.

The anion exchange resin employed must, of course, be activated and thismaybe done in the conventional manner by treatment with a dilutealkaline substance such as, e. g., a 0.1 %10% solution of sodiumhydroxide, sodium carbonate, a corresponding potassium salt, etc.

The present invention is particularly advantageous when applied to theseparation by magnetic means of a single magnetic resin from a pluralityof. non-magnetic resins in admixture therewith.

Various combinations of separation processes may be utilized. Forexample, the mixture of ion exchange resins used in a liquiddemineralization process may be separated from. the demineralized liquidby means of froth flotation. The resinous components of the mixture maythen be separated, one from the other, by means of a sink and floatprocedure or, according to the process of the present invention, bymagnetic means providing, of course, that one of the resinous componentshas been made magnetic before its use. Obviously, any desiredcombination of various separation procedures may be used.

It is also possible to so adjust the density of a particular resin bymeans of the magnetic substance used to render it magnetic that afterbulk magnetic recovery of a mixture of magnetic resins from a liquidmedium, the more dense resin may be separated by sink and floattechniques from the less dense resin.

The term ionizable solids or ionizable materials is intended to includeboth volatile and non-volatile materials. The major proportion of thesesolids are inorganic, but some organic substances may be included. Theseionizable solids are impurities in, the sense that they are not desiredin admixture in the fluid to be purified but they may in themselves bevaluable or desirable materials.

I claim:

1. A process which comprises bringing a liquid containing ionizablesolids into contact with a mixture of a magnetic cation exchange resinand an anion exchange resin until the mixture of resins no longer has acapacity for removing ion izable solids from the liquid, removing themixture of exhausted resins from said liquid, and separating the cationexchange resin from the anion exchange resin by magnetic means.

2. A process which comprises bringing a liquid containing ionizablesolids into contact with a mixture of a magnetic cation exchange resinand an anion exchange resin until the mixture of resins no longer has acapacity for removing ionizable solids from the liquid, separating themixture of exhausted resins from said liquid, and separating the cationexchange resin from the anion exchange resin by magnetic means, bringingthe separated magnetic cation exchange resin into contact with a dilutesolution of an acid,

bringing the separated anion exchange resin into contact with a dilutesolution of an alkali, mixing the so-reactivated cation andanion-exchangeresins together and bringing a liquid, containingionizable solids into contact with the mixture.

3. A process which comprises bringing a liquid containing ionizablesolids into contact with a mixture of a magnetic ion exchange resin anda non-magnetic ion exchange resin, the two resins having oppositepolarity, until the mixture of resins no longer has-a capacity forremoving ionizable solidsfrom the liquid, removing the mixture ofexhausted resins from the said liquid, and separating the magnetic ionexchange resin from the non-magnetic ion exchange resin by'mag-neticmeans. I

- EARL C. HERKENHQFF.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 861,782 Wait July 30, 1907 1,494,070 MacKnight May 13, 19241,682,364 Ballantine et al. Aug. 28, 1928 1,683,780 Hulsmeyer Sept. 11,1928 1,982,689 Polydoroff Dec. 4, 1934 2,197,931 Jacobs 1 Apr. 23, 19402,198,378 Ellis Apr. 23, 1940 2,275,210 Urbain Mar. 3, 1942 2,352,324Hubler 1 June 27, 1944 2,365,720 Neighbors Dec. 26, 1944 2,412,668Bandur Dec. 17, 1946 2,434,190 Barnes Jan. 6, 1948 2,461,505 -DanielFeb. 15,1949

OTHER R ERENCES Akeroyd: Journ. Physical Chemistry, vol. 42, 1938, pp.343-352, I

Mccullochz Disinfection and Sterilization, 1945, Lea and Febiger,Philadelphia, p, 263.

A. P. C. application of Pieter Smit, Ser. No, 359,575, published May 11,1943.

2. A PROCESS WHICH COMPRISES BRINGING A LIQUID CONTAINING IONIZABLESOLIDS INT CONTACT WITH A MIXTURE OF A MAGNETIC CATION EXCHANGE RESINAND AN ANION EXCHANGE RESIN UNTIL THE MIXTURE OF RESINS NO LONGER HAS ACAPACITY FOR REMOVING IONIZABLE SOLIDS FROM THE LIQUID, SEPARATING THEMIXTURE OF EXHAUSTED RESINS FROM SAID LIQUIDS, AND SEPARATING THE CATIONEXCHANGE RESIN FROM THE ANION EXCHANGE RESIN BY MAGNETIC MEANS, BRINGINGTHE SEPARATED MAGNETIC CATION EXCHANGE RESIN INT CONTACT WITH A DILUTESOLUTIN OF AN ACID, BRINGING THE SEPARATED ANION EXCHANGE RESIN INTOCONTACT WITH A DILUTE SOLUTION OF AN ALKALI, MIXING THE SO-REACTIVATEDCATION AND ANION EXCHANGE RESINS TOGETHER AND BRINGING A LIQUIDCONTAINING IONIZABLE SOLIDS INTO CONTACT WITH THE MIXTURE.